Relax title/credit input format rules

[anoved]

It is easy enough to manually pre-format the first few lines, but add some options/logic to allow arbitrary files to be printed. Maybe only look for the header lines if instructed via --flags.

[anoved]

Fixed in ffc1bf8. Reads pre-formatted title and subtitle lines if instructed via --header flag. Accepts explicit --title and --subtitle parameters. Otherwise, prints text content without any titles.